Differences in Karyotype and Fluorochrome Banding Patterns among Variations of Trichosanthes cucumerina with Different Fruit Size
Differences in Karyotype and Fluorochrome Banding Patterns among Variations of Trichosanthes cucumerina with Different Fruit Size
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DOI：
10.1508/cytologia.84.237
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发表时间：
2019-09-01
期刊：
影响因子：
1
通讯作者：
Jha, Sumita
中科院分区：
文献类型：
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作者：
Bhowmick, Biplab Kumar;Jha, Sumita
丝瓜是一种重要的农业葫芦科蔬菜，目前被公认为瓜丝瓜的‘Anguina’品种。黄瓜属植物。野生型植物自然产生小果实(TCSF)，因此可以与果实较大的栽培品种(TCLF)区分开来。目前，用现代细胞遗传学方法研究这两种植物的染色体特征是十分必要的。染色体制备采用酶浸渍-风干法(EMA)标准化。尽管这些品种的染色体数目相同(2n=22)，但它们的核型与TCSF植株有很大的不同。基于EMA-DAPI的减数分裂细胞制片再次确认了配子染色体数目(n=11)，并在两种类型的植株中表现出规则的染色体行为。用14个染色体间和染色体内对称性/不对称性指数进行的染色体形态计量学研究表明，TCLF的核型具有较高的不对称性。体细胞染色体的荧光显带表明，CMA和DAPI带在不同类型植物中的分布存在差异。TCSF植株的特征是在两对具有次生收缩的染色体上出现CMA带，而在所有补体的染色体上都发现了DAPI带。相反，在TCLF中完全没有DAPI条带，而在2对有次生皱缩的染色体和1对其他染色体上出现了远端CMA带。CMA-DAPI带型和核型参数对核型关系的评价有重要影响。在主成分分析图和UPGMA物候图上，TCSF和TCLF分别形成了不同的类群和聚类图。TCSF和TCLF植物在核进化状态和荧光带型上的差异可用于进一步的细胞分类学和系统发育研究。
Snake gourd is an agriculturally important cucurbit vegetable recognized presently as the cultivar 'Anguina' of Trichosanthes cucumerina ssp. cucumerina. The wild type plant occurs naturally that produces small fruits (TCSF) and thus can be distinguished from the cultivar with large elongated fruits (TCLF). Presently, chromosomal features were revealed by modern cytogenetic methods to characterize the two types of plants. Chromosome preparations were standardized by an enzymatic maceration and air-drying method (EMA). The cultivars had considerably different karyotypes than the TCSF plants in spite of the same chromosome numbers (2n=22). EMA-DAPI based meiotic cell preparations reconfirmed gametic chromosome number (n=11) and showed regular chromosome behavior in both plant types. Karyomorphometric study with 14 inter- and intra-chromosomal symmetry/asymmetry indices advocated higher asymmetry in the karyotype of TCLF. The fluorochrome banding pattern of somatic chromosomes revealed the differential distribution of CMA and DAPI bands in the types of plants. TCSF plants were characterized by the presence of CMA bands in two pairs of chromosomes with secondary constrictions while DAPI bands were found in all chromosomes of the complements. On the contrary, DAPI bands were completely absent in TCLF while distal CMA bands were scored in two pairs of chromosomes with secondary constrictions and one pair of other chromosomes. CMA-DAPI banding patterns and karyomorphometric parameters had a significant impact on the evaluation of karyotype relations. The plants of TCSF and TCLF formed distinct groups and clusters in PCA plot and UPGMA phenogram, respectively. The variation in karyoevolutionary status and fluorochrome banding pattern between TCSF and TCLF plants could be utilized for further cytotaxonomic and phylogenetic revisions.